This invention relates generally to inkjet printhead construction, and more particularly, to wide-array inkjet printhead construction.
There are known and available commercial printing devices such as computer printers, graphics plotters and facsimile machines which employ inkjet technology, such as an inkjet pen. An inkjet pen typically includes an ink reservoir and an array of inkjet printing elements, referred to as nozzles. The array of printing elements is formed on a printhead. Each printing element includes a nozzle chamber, a firing resistor and a nozzle opening. Ink is stored in the ink reservoir and passively loaded into respective firing chambers of the printhead via an ink refill channel and ink feed channels. Capillary action moves the ink from the reservoir through the refill channel and ink feed channels into the respective firing chambers. Conventionally, the printing elements are formed on a common substrate.
For a given printing element to eject ink a drive signal is output to such element""s firing resistor. Printer control circuitry generates control signals which in turn generate drive signals for respective firing resistors. An activated firing resistor heats the surrounding ink within the nozzle chamber causing an expanding vapor bubble to form. The bubble forces ink from the nozzle chamber out the nozzle opening.
A nozzle plate adjacent to the barrier layer defines the nozzle openings. The geometry of the nozzle chamber, ink feed channel and nozzle opening defines how quickly a corresponding nozzle chamber is refilled after firing. To achieve high quality printing ink drops or dots are accurately placed at desired locations at designed resolutions. It is known to print at resolutions of 300 dots per inch and 600 dots per inch. Higher resolution also are being sought
There are scanning-type inkjet pens and non-scanning type inkjet pens. A scanning-type inkjet pen includes a printhead having approximately 100-200 printing elements. A non-scanning type inkjet pen includes a wide-array or page-wide-array printhead. A page-wide-array printhead includes more than 5,000 nozzles extending across a pagewidth. Such printhead is controlled to print one or more lines at a time.
In fabricating wide-array printheads the size of the printhead and the number of nozzles introduce more opportunity for error. Specifically, as the number of nozzles on a substrate increases it becomes more difficult to obtain a desired processing yield during fabrication. Further, it is more difficult to obtain properly sized substrates of the desired material properties as the desired size of the substrate increases.
In the related matter, cross-referenced above, a scalable wide-array printhead structure is described in which multiple inkjet printhead dies are mounted to a carrier substrate. One of the challenges in forming a wide array printhead with multiple printhead dies is the number of interconnections which occur. Many electrical interconnections are needed. In addition, many ink connections are required to deliver the inks. In a three-color, four inch, wide-array printhead having 34 printhead dies, for example, there are at least 102 fluid interconnections (i.e., 3xc3x9734=102).
One aspect of the present invention provides an inkjet pen. The inkjet pen includes a multilayered platform, an electrical interconnection extending through the multilayered platform, and a plurality of printhead dies each mounted on the multilayered platform. The multilayered platform includes a first layer having an ink inlet defined therein, a second layer having a plurality of ink feed slots defined therein, and at least one third layer having an ink manifold defined therein. As such, the ink manifold of the at least one third layer fluidically couples the ink inlet of the first layer with the ink feed slots of the second layer. Each of the printhead dies are mounted on the second layer of the multilayered platform and include an array of printing elements and an ink refill slot communicating with the array of printing elements. As such, the ink refill slot of each of the printhead dies communicates with at least one of the ink feed slots of the multilayered platform, and each of the printhead dies are electrically coupled to the electrical interconnection.
According to one aspect of the invention, an inkjet pen includes the multilayered ceramic substrate. Ink is received from an ink reservoir at an inlet opening. The ink flows through a manifold to a plurality of ink feed slots adjacent to corresponding printhead dies. The printhead dies are mounted to a first side of the carrier substrate. Each printhead die includes an array of printing elements and an ink refill slot. Each one of the plurality of printhead dies receives ink at the ink refill slot from the reservoir by way of the carrier substrate""s ink feed slot. Ink flows from the die""s refill slot to the printing elements. For a recirculating ink system, ink leaves the manifold back toward the reservoir through an outlet opening.
According to another aspect of the invention, the inkjet manifold is formed within the carrier substrate. Layers of the carrier substrate include overlapping slots which, when the layers are stacked, define ink channels which carry ink from one side of the carrier substrate (e.g., adjacent the ink reservoir) to the other side of the carrier substrate (e.g., to the printhead dies). The reservoir is fluidly coupled to one side of the carrier substrate. The printhead dies are fluidly coupled to the other side of the carrier substrate.
According to another aspect of the invention, layers of the carrier substrate include slots which define a portion of one or more manifold channels and electrical wiring lines for interconnecting the printhead dies.
According to another aspect of the invention, a manifold channel may be of various shapes, such as a large cavity or a serpentine channel. The ink inlet opening occurs in one layer of the substrate. For a recirculating system the outlet opening back to the reservoir also occurs in such one layer. The manifold channel extends through the layers of the substrate to a plurality of ink feed slots open in another layer of the substrate. The printhead dies are mounted adjacent to such ink feed slots in such other layer.
According to another aspect of the invention, the pen includes multiple reservoirs, one for each color of ink. Separate inlet openings and manifold channels are formed in the carrier substrate to pass ink from a respective reservoir to the printhead dies. A first fluid path occurs from a first inlet opening to a first set of the ink feed slots and a second fluid path occurs from a second inlet opening to a second set of ink feed slots.
The inkjet pen is part of a printing system which also includes a housing, a mounting assembly, a media transport assembly, and a controller. The inkjet pen is positioned at the mounting assembly and includes a plurality of printing elements. A print zone occurs adjacent to the plurality of printing elements along a media path. The media transport assembly moves a media sheet along the media path into the print zone. The controller determines a timing pattern for ejecting ink from the plurality of printing elements onto the media sheet.
According to another aspect of the invention, one method for loading the plurality of inkjet nozzles, includes replacing the internal reservoir of the pen, and flowing ink from the internal reservoir into the ink manifold of the carrier substrate. The carrier substrate has an inlet opening coupled to the internal reservoir. The ink manifold fluidly connects the inlet opening to a plurality of ink feed slots at the carrier substrate. The ink feed slots are positioned adjacent to ink refill slots of printhead dies which are mounted to the carrier substrate. Ink flows into the respective ink refill slots, then into a plurality of nozzle chambers. Ink is fired from the nozzle chambers to print onto a media sheet.
One advantage of the invention is that a manifold for handling multiple colors of ink is formed in an unitary printhead assembly. These and other aspects and advantages of the invention will be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.